Volume 2,1 (1963) - Dansk Dendrologisk Forening

mostly spread among other trees seldom forming pure stands. Its
needles are linear, often a little curved, dark green to bluish green,
isolateral with lots of stomata on both sides and quite devoid of
serration. The cones are large for a Hemlock, in size and shape reminding
of those of Picea glauca. I have got the impression that it is
a light-loving pioneer tree, but rather slow growing. The top-shoot is
not or only slightly overhanging.
T. Jeffreyi is, as far as I have seen, met with wherever the two
former Tsuga-sipecies grow near each other. The type has quite intermediate
needles, these being slightly serrate, broad linear, with a
considerable number of stomata on the upper side, but to a certain
degree dorsiventral. The cones are nearly half the size of those of
Mertensiana, but have the same Pzcea-like shape. In the Canadian
forest literature it is mentioned that intergrades between Mountain
and Western Hemlock some times may be found in high altitudes,
and I found whenever I climbed to the transition zone between the
two main species that a long series of intermediates as to structure
of leaves and shape of the trees easily could be demonstrated there.
Concerning the cones they seemed to be either heterophylla cones or
cones of Mertensiana-sh&pe varying in size from that of Jeffreyi cone
to that of a true Mertensiana cone.
I am of the opinion that T. Jeffreyi is a hybrid Fl's and backcrosses
both of the parents. As a longliving tree and as a pioneer it
is more often met with than usually is the case in hybrids, and I
should like to call it a woody parallel to the above mentioned Geumhybrid
and like it being of full or nearly full fertility.
6. Picea glauca (Moench) Voss, Picea Engelmanni (Parry) Engelm.
and Picea sitchensis (Bong.) Carr. are three important and apparently
easily distinguishable American trees. Here in Denmark we are
accustomed to find the hybrid between White Spruce and the Sitka
spruce whenever seeds are gathered on Sitkas not too far from White
Spruces. In their homeland they only reach each other in some places
in Alaska, and I was told that hybrids occurred, but I did not go
there. As to P. glauca and P. Engelmanni I was greatly astonished
when Canadian foresters told me that it was quite impossible to
distinguish between these two species, I really did not believe it.
Fortunately I got a chance to study the two trees on several growing
places in the Canadian Cascades and in The Gold Range and in the
Selkirk Mountains. The P. glauca growing there is the very characteristic
variety Albertiana having bark, needles and cones like those
of the common eastern White Spruce but distinguished by hairy